Orifice
Orifice , noun
[French, from Latin orificium; os, oris, a mouth + facere to make. See Oral, and Fact.]
A mouth or aperture, as of a tube, pipe, etc.; an opening; as, the orifice of an artery or vein; the orifice of a wound. — Shakespeare
Etna was bored through the top with a monstrous orifice.